Jordan's Salamander

This species is characterized by a dull bluish-grey belly and by red cheeks with a pale background color that contrasts markedly with the top of the head, which is deep brown (Hairston and Pope 1948, Hairston 1950, and Bishop 1943). The ventral surface of the head is a dull flesh color that blends with the belly. The ventral surface of the tail is darker than the belly, but lighter than the dorsal surface, which is blue-black. The legs and feet are also a slightly lighter grayish-brown. The color of the cheeks can range from dull pink to bright red, and the area is limited behind by the lateral extensions of the gular fold, above by the impressed line running from the eye to the gular fold, in front by the eye, and below, anteriorly, by the lower margin of the upper jaw (Bishop 1943). Juveniles have pale bellies and all individuals less than 29 mm have red spots on dorsum, but not on cheeks (Hairston and Pope 1948). The head is widest immediately behind the eyes, where it appears slightly swollen. Behind this, the sides converge very slightly to the lateral extensions of the gular fold. In front of the eyes, the sides taper abruptly to a pointed snout. The eyes are large and protuberant and the gular fold is well developed. A deep sinuous groove stretches from the posterior angle of the eye to the lateral extension of the gular fold, and from here a short vertical groove runs to the angle of the jaw. The trunk is moderately stout, well rounded above and on the sides, and slightly flattened beneath. The tail is nearly circular in cross section at the base and evenly tapers to a slender tip. There are 15-16 costal grooves, including 1 in the axilla, which is usually poorly developed, and 1 in the groin, where 2 frequently run together. There are 2-3 intercostal spaces between the toes of appressed limbs. The limbs are stout and larger than in most species of Plethodon. There are four fingers, which in order from longest to shortest are either 3-4-2-1 or 3-2-4-1, and which have no webbing between them. There are 5 toes, which in order from longest to shortest are 3-4-2-5-1, with the innermost toe being rudimentary (Bishop 1943). Number of vomerine teeth ranges from 5 to 11, with an average of 8 (Hairston and Pope 1948). The series of teeth arises behind or just outside the outer edge of the nares and curves gently inward and backward toward the mid-line, where they are separated by about twice the diameter of an inner naris. The parasphenoid teeth are in a large patch narrower in front than in back. The patch is rounded in the back and a narrow, elongate area free of teeth runs through the center. The tongue is fairly large, and the margins are thick and smooth (Bishop 1943). Average length of 10 adults of both sexes was 112.5 mm. The largest specimen, a female, had a total length of 135 mm with a tail length of 65 mm, head length of 18 mm, and head width of 10 mm. Proportions of a male were total length of 119 mm with tail length of 60.5 mm, head length of 14 mm, and head width of 9 mm. The tail always comprises about half of the body length (Bishop 1943). Individuals are larger at lower elevations. Males can be identified year-round by conspicuous cloacal lips and a slightly more pointed lower jaw, and during breeding season by distinct mental glands (Hairston 1983 and Bishop 1943).The species authority is: Blatchley, W. S. 1901. "On a small collection of batrachians from Tennessee, with descriptions of two new species." Indiana Department of Geology and Natural Resources Annual Report for 1900 25: 759–763.This species was featured as News of the Week on 16 November 2020: To improve predictions for how species will respond to our changing climate, we should not neglect the behavioral consequences of climate change. Gade et al. (2020) set out to address this shortcoming: they wanted to project how the changing conditions of the next century will influence salamander surface activity. They conducted surveys of three species of the Plethodon jordani complex in the Appalachians of the US, identified predictors of salamander surface activity and abundance (temperature and water vapor pressure), then used this relationship to explore how the surface activity of P. jordani complex species will respond to stabilization and high emissions climate scenarios. They found that the probability of salamander surface activity during peak active season increased over time, though gladly temperatures were not predicted to surpass the species' thermal maxima. Surface activity is important to salamanders because it their opportunity to forage and mate, so this outcome may sound like good news. However, the authors qualify that there are physiological trade-offs at play, so modified behavioral patterns can have unpredictable consequences. For example, higher temperatures increase metabolism and may decrease the energy assimilation of salamanders, which can result in smaller body sizes and lower growth rates, and in turn, result in delayed sexual maturity and lower fecundity. The authors show how the examination of behavior like surface activity, critical to their fitness, can reshape our understanding of how species will fare with a changing climate (Written by Emma Steigerwald).

Plethodon jordani is found in the Great Smoky Mountains from Mt. Sterling to the mountains north of Bryson City, NC (Hairston and Pope 1948). Hybridization occurs with congener P. metcalfi at Hyatt Ridge, which connects the Great Smoky Mountains with the Balsams in the southeast corner of Great Smoky Mountains National Park (Hairston 1950). The zone of hybridization is 4230 m wide and stretches from Spruce Mountain to Heintooga Overlook (Hairston et. al. 1992). Hybrids show differing amounts of red on the cheek and differing darkness of the belly (Hairston 1950). Transplantation of both species between the two mountain ranges yielded a much lower frequency of hybrids then would be expected from random mating, thus suggesting that either strong selection against hybrids or positive assortative mating occurs. This may be due to the large genetic divergence between the two species, which have a Nei genetic distance of 0.27 (Highton 1998). Another zone of hybridization occurs with congener P. shermani and stretches along a line from Franklin, NC to Andrews, NC. These hybrids are characterized by both red cheeks and red legs (Hairston 1950). A final hybrid exists with congener P. teyahalee in the narrow altitudinal zone where the two species overlap. These hybrids occur throughout the range of P. jordani, but only account for 0.05% of the population (Hairston 1980). This hybrid is characterized by a mixture of red on the cheeks and white spots on other parts of the body.The lowest elevation at which an individual has been found is 2850 ft and from there they range up to the top of Clingman's Dome, the highest point in the Great Smoky Mountains at 6643 ft (Hairston 1948). The lowest elevation at which P. jordani occurs on any particular slope is mediated by local climate and changes with the direction of the slope face (Hairston 1951). Individuals normally occur down to 900 m on north-facing slopes and down to 1500 m on south-facing slopes (Hairston, Nishikawa, and Stenhouse 1987).Plethodon jordani is favored by a wet and cool climate, which is normally found in the upper elevations (Hairston 1973). It occurs on heavily forested slopes and can be found among the leaf litter or under old rotten logs or bark. P. jordani is sympatric with 10 other species of salamanders and comprises 73.6% of the individuals (Hairston 1980). Its abundance is about 0.7 individuals/m2 (Hairston 1996).

There is no consistent trend in the number of individuals of P. jordani based on observations made at Heintooga Overlook since 1972 (Hairston 1993). The only major threat is clearcutting, which has reduced salamander populations in the southern Appalachians by almost 9%, or more than one-quarter of a billion salamanders (Alford and Richards 1999). Logging exposes terrestrial salamanders to altered microclimates, increased soil compaction and desiccation, and reduced habitat complexity.

Seasonality of P. jordani varies with elevation, but individuals are mainly active from mid-May to early October, reaching their greatest abundance from July to September (Hairston 1981). They emerge from their burrows at the beginning of the night and forage until about 0100 h, when activity begins to die off (Hairston 1987). On any particular night about one-quarter of the individuals are active (Hairston 1984). They are generalist predators that feed on any moving organism of appropriate size (Hairston, Nishikawa, and Stenhouse 1987). They rely mostly on the visual cues of size and velocity to identify prey (Schuelert and Ursula 2002). Pulmonata, Myriapoda, and Coleoptera each compose over 10% of the diet. Foraging usually takes place on the forest floor, but on humid, foggy nights many individuals can be observed climbing on low herbaceous plants (Hairston, Nishikawa, and Stenhouse 1987). Mating occurs in August and September. P. jordani are territorial and territories are 11.5 m2 for males, 2.8 m2 for females, and 1.7 m2 for juveniles (Merchant 1972). Pheromones are used to communicate and are applied to the substrate and sensed by touch (Hairston 1985). Males can differentiate between the sexes based on odor and prefer the odor of the female (Dawley 1984). Once air temperatures fall as low as 0° in the fall, no surface activity is seen until the following year as the salamanders winter in their burrows deep underground. Eggs are laid underground in May and take two months to hatch. Clutch size is directly related to snout-vent length, which is directly related to age. This allows average clutch size to vary from 3-10 eggs based on the age of the female. The female guards the eggs from predation and parasitism, and survival of the clutch has never been observed without survival of the mother (Hairston 1983). Metamorphosis takes place before hatching, so offspring emerge as miniature adults and there is no aquatic larval stage (Hairston, Nishikawa, and Stenhouse 1987). Juveniles begin to emerge in May the year after they hatched. At this time their snout-vent length averages 16.64 mm (Hairston 1983). More one-year olds continue to emerge as the summer progresses, and it is not until September that they reach a number proportional to that of the older age classes. Average growth in snout-vent length during May-October of the second year is 12.02 mm. This is followed by an average growth of 1.90 mm during the winter and then another 9.26 mm of growth from May-October of the third year (Hairston 1983). In May, four age classes can be identified: 1 year-olds, 2 year-olds, 3-year olds, and those 4 years or older. By October, however, the 3 year-olds have merged with the adults. About one-quarter of the salamanders become mature during the third year, and another quarter during the fourth year. By the time they reach their fifth year, all P. jordani are mature, but females still alternate years in which they oviposit. This is due to the fact that it is difficult to capture enough food after laying eggs in May in order to produce enough energy to have a new batch of eggs by the time cold weather halts mating (Hairston 1983). Survival is highest during the first year at 0.837 when the juveniles remain underground. It is lowest during the second year at 0.364, rises during the third year to 0.484, and is 0.81 for each subsequent year. This creates a relatively long mean generation time for such a small creature of 9.8 years (Hairston 1983). Plethodon jordani is in intense competition with its congener P. teyahalee where they overlap in a narrow altitudinal zone that ranges from 70-120 m in height (Hairston 1980). Below this narrow altitudinal zone the climate is warmer and drier, giving P. teyahalee an advantage, while above this narrow altitudinal zone the climate is cooler and drier, giving P. jordani an advantage. If P. teyahalee is removed from the area of overlap, the proportion of 1 year-old and 2 year-old P. jordani increases. If P. jordani is removed from the area of overlap, the population of P. teyahalee increases by roughly 350% (Hairston 1980). This competition is due to alpha-selection, evolution of interference mechanisms against competing species, in both P. jordani and P. teyahalee (Hairston 1983). This alpha-selection can be seen in the greater aggressiveness of P. teyahalee in the Great Smoky Mountains, where it overlaps with P. jordani, as compared to its aggressiveness in the Balsams, where there is no P. jordani to compete with. P. jordani has also evolved to be much more aggressive than its close relative P. metcalfi, which also overlaps with P. teyahalee. This aggressive interference determines the extent to which the two species can exclude each other from the intermediate elevations (Hairston, Nishikawa, and Stenhouse 1987).Plethodon jordani responds to snake predation by writhing, trashing, tail wrapping, tail autonomy, and biting. These actions are effective roughly one-third of the time (Feder and Arnold 1982). Like all other large species of Plethodon in the eastern United States, P. jordani possesses a tail that exudes a great deal of slime when it is disturbed. This slime may stick to the feathers around the eyes of bird predators and interfere with vision by gluing the eyelids shut (Highton 1995). P. jordani does not undertake any migrations and average variance in movement is only 1 m every 7.85 days (Nishikawa 1990). The maximum aerobic speed of P. jordani is 0.16 km/h, which increases O2 consumption to 6-9 times standard rate. Lower levels of exercise, however, can be maintained for over 2 hours (Full 1986).

Maximum longevity: 19.8 years (captivity) Observations: One study in the wild found that 77% of these animals survive to age 10 (Hairston 1983), so maximum longevity could be underestimated.

Plethodon jordani is a large species of Plethodon that varies in color according to locality. The dorsal color varies from slate gray to bluish black and the back usually lacks both red pigments and white spots. Depending on geographic location, the adults may be unmarked or have red cheeks (Great Smoky Mountains, Tennessee), red legs (Nantahala and Tusquitee mountains and on Cheoah Mountain, North Carolina), reddish frosting on the back (extreme northwestern South Carolina and on Fishhawk Mountain, North Carolina), or gold frosting on the back in the southernmost part of their range. Jordan's salamanders have sixteen costal grooves. Adults average 12.5 cm in total length.

Range length: 9 to 18.4 cm.

Average length: 12.5 cm.

Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry ; poisonous

Sexual Dimorphism: sexes alike

There are disagreements in the literature with species and subspecies distinctions. According to the latest data, color variation and geographic location are the two main factors in determining the species identification of a particular salamander. There are disagreements in the literature with species and subspecies distinctions.

The Plethodon jordani complex was recently recognized by Highton and Peabody (2000), which contains 7 species (P. jordani, P. metcalfi, P. shermani, P. cheoah, P. amplus, P. meridianus, and P. montanus). The splitting of P. jordani appears to be gaining acceptance.

The most common form of communication for Plethodon jordani is the use of pheromones. These chemicals play a key role in courtship behaviors and the act of mating.

Communication Channels: visual ; tactile ; chemical

Other Communication Modes: pheromones ; scent marks

Perception Channels: visual ; tactile ; chemical

Populations of Plethodon jordani and other salamanders are often absent or greatly reduced in number on recent clear-cuts in western North Carolina. Less intensive harvesting practices that leave the basic structure of the forest intact would benefit this and other salamander species in southern Appalachian forests.

Highton (2005) noted significant decline (>40%) across the range of Plethodon. Logging roads, even those no longer in use, have been shown to negatively affect Plethodon abundance.

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

IUCN Red List of Threatened Species: near threatened

Common garter snakes (Thamnophis sirtalis) are the largest threats to Plethodon salamanders. The first defense mechanism of Jordan’s salamanders is the bright red cheeks or legs possessed by some individuals. This aposematic coloration is a warning sign to predators. Snake predation upon Plethodon salamanders also elicits other behaviors, including writhing and thrashing movements that coat the predator with slimy secretions, tail autotomy (tail loss), and biting. Bennett and Licht (1974) suggested that the particular antipredator behaviors of amphibian species are correlated with the extent of anaerobiosis during a burst of activity. According to a study by Arnold and Feder (1982), predatory encounters are especially suitable for demonstration of anaerobiosis during spontaneous natural activity, if it does occur. In one trial conducted by Arnold and Feder (1982), a Jordan's salamander escaped the snake by producing thick secretions which actually glued the snake to the substrate (rendering it immobile). Predatory birds are also likely to be important predators of Jordan's salamanders, especially at higher elevations where there are fewer garter snakes.

Known Predators:

• common garter snakes (Thamnophis sirtalis)
• predatory birds (Aves)

Anti-predator Adaptations: aposematic

Nests of Plethodon jordani have never been found. Gravid females move underground in late spring or early summer and oviposit in deep underground recesses. Females oviposit in May and hatching usually occurs in late summer or early autumn, about 2 to 3 months after the eggs were deposited. Newborns remain underground for 10 to 12 months after hatching. Metamorphosis occurs before hatching, so individuals emerge from eggs in small adult form, there is no aquatic larval stage. Small individuals judged to be nearly 1 year old first appear on the surface in May or June. Individuals increase by an average of 12 mm (snouth-vent length) between May and October of their second year.

Development - Life Cycle: metamorphosis

Plethodon jordani has a mean generation time of 9.8 years, with 77% surviving to 10 years old.

Average lifespan
Status: wild: 9.8 years.

Plethodon jordani is restricted to cool, mesic forests. Jordan's salamanders are found in areas with high annual precipitation from deep mountain gorges to the ridgeline in suitable habitat. Populations occur at their lowest elevations in the southern portions of their range. Individuals are most often found on the forest floor during the night when they emerge to forage, they are sometimes found under logs and rocks during the day, although they mostly remain underground when not foraging. Jordan's salamanders are most abundant in red spruce (Picea rubens) - Fraser fir (Abies fraseri) forest but are also found on hardwood-covered ridges. The forest floor where this species is most abundant is covered with a heavy layer of moss with only a little soil over a mass of large boulders.

Range elevation: 213 to 1951 m.

Average elevation: 763 m.

Habitat Regions: temperate ; terrestrial

Terrestrial Biomes: forest ; mountains

Plethodon jordani ranges from southwestern Virginia to extreme northeastern Georgia. Plethodon jordani has been collected from elevations of 213 to 1951 m, but populations are usually constrained to elevations above 600 m.

Biogeographic Regions: nearctic (Native )

Both male and female salamanders eat the same type and size of prey. On dry nights the majority of individuals will forage on vegetation, whereas, on wet nights, they will roam the forest floor in search of invertebrate prey. Food items in 204 specimens from the Great Smoky Mountains included annelids, snails, millipedes, centipedes, isopods, phalangids, pseudoscorpions, mites, spiders, and a variety of insects. Millipedes are more important during the spring and insect larvae are more important during the fall. Collembolans and annelids tend to increase in importance in higher altitudes. In a study performed by Whitaker and Rubin (1971), the 10 most important prey by volume were: ants, spiders, lepidopteran larvae, beetle larvae, collembolans, millipedes, centipedes, mites, snails, and dipteran larvae.

Animal Foods: insects; mollusks; terrestrial worms

Plant Foods: wood, bark, or stems; flowers

Primary Diet: carnivore (Insectivore , Eats non-insect arthropods, Molluscivore , Vermivore); herbivore (Folivore )

Hairston et al. (1956) conducted a series of studies on interspecific relationships between P. jordani and P. oconaluftee in the southern Appalachians. In all the studies, the researchers found that the removal of P. jordani caused an increase in P. ocanaluftee. Removal of P. ocanaluftee did not affect P. jordani but did increase the proportion of juveniles in the population. Hairston et al. concluded that competition did exist between the two species but they could not conclude which resource they were competing for.

There is no known benefit provided to humans from Plethodon jordani

There are no known adverse effects of Plethodon jordani on humans.

Courtship begins when a male approaches a female and being to nudge or tap her with his snout. The male then places his mental gland on the female's nasolabial grooves and begins a "foot dance". The foot dance is described as the limbs being raised and lowered off the ground one at a time. The male then moves towards the female's head. The male turns his head under the female's chin and lifts. The male then begins to circle under the female's chin and laterally moves his tail as he circles her. If the female is responsive, she places her chin on his tail and moves forward to the base of his tail. The couple then engages in a tail-straddle walk that may last for an hour. During the walk the male may turn and slap his mental gland on the female's nasolabial region. The male eventually stops moving and begins a series of lateral rocking movements of his sacrum. The female begins with a series of head movements, opposite to the rocking movements of the male. The male then presses his vent to the substratum and releases a spermatophore. Next he flexes his tail to one side and leads the female forward. She stops when her vent is over the spermatophore, then lowers her sacrum and picks up the sperm cap. During this process the male arches the sacral region and does "push-ups" with his hind limbs. The pair usually splits up after the spermatophore is deposited even if the female is unsuccessful at picking it up.

Females may court several times and mate with two or more males in one season. Males will often attempt to mate other males and mimic the behaviors of a female. This is a form of competition in which males cause other males to waste their gametes. In a laboratory study, researchers inhibited females from smelling the male's pheromones, which greatly reduced the response of the female to the courtship ritual. In most cases the female did not respond at all to the male during courtship behavior.

Mating System: polygynandrous (promiscuous)

Male Plethodon jordani mature sexually at approximately 3 years of age. An estimated 25% of females oviposit for the first time 4 years after hatching, another 25% oviposit for the first time 1 year later. The remaining 50% wait until they are 6 years old before they oviposit for the first time. After their first oviposit, females reproduce every other year for the remainder of their lives. Clutch sizes of 3 to 10 have been estimated.

Breeding interval: Female Plethodon jordani reproduce every other year after becoming sexually mature.

Breeding season: Gravid females go underground in late spring or early summer. They oviposit in May.

Range number of offspring: 3 to 10.

Range time to hatching: 2 to 3 months.

Average time to independence: 1 years.

Range age at sexual or reproductive maturity (female): 4 to 6 years.

Average age at sexual or reproductive maturity (male): 3 years.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); oviparous

Parental Investment: no parental involvement; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female)

The red-cheeked salamander (Plethodon jordani), also known as the Jordan's salamander, Jordan's redcheek salamander, or Appalachian woodland salamander, is a species of salamander in the family Plethodontidae. It is endemic to the Appalachian Mountains in the eastern United States.